2. GPS
“Provide accurate positioning anywhere in the world”
• Satellite based navigation system
• Based on a constellation of about 33 satellites
• Developed by the United States Department
of Defense (DOD)
No subscription fees or setup charges
to use GPS.
3. HOW GPS DETERMINES A LOCATION
• Current locations of GPS satellites
• The distance between Receiver’s Position
and the GPS satellites
• GPS satellites are orbiting the earth at an
altitude of 20,180 miles and orbits are
segmented
The orbits and locations of the satellites are
known in advance
4. …Location
• Distance is the amount of time taken by radio signal
(the GPS signal) to travel from the satellite to the
receiver
• Radio waves travel at the speed of light, i.e. about
186,000 miles per second
distance = speed x time
5. GPS Error
• Sometimes waves get distracted because of
atmosphere or bouncing of waves occur due to
reflecting path
Waves deviation is with in range of 50-100 m
• The solution comes with the Dual Frequency
receivers that provide position in sub-centimeters.
